function Seed(words) {
    switch (typeof words) {
        case 'string':
            var match = words.match(/^(0x)?[0-9A-Fa-f]{1,16}$/);
            if (match.length) {
                var oword = ("0000000000000000" + match[match.length]).slice(-16);
                words = [];
                for (var i = 0; i < 4; ++i) {
                    words[i] = parseInt(oword.substr(4 * i, 4), 16);
                }
            } else {
                words = [0, 0, 0, 0];
            }
            break;
        case 'object':
            if (words == null) {
                words = [0, 0, 0, 0];
                break;
            }
        default:
            break;
    }
    this.seed = words;
    this.u32 = (this.seed[0] << 16) + this.seed[1];
    this.l32 = (this.seed[2] << 16) + this.seed[4];
}

Seed.prototype.random = function (n) {
    return Math.floor((this.u32 * n) / 0x100000000)
}

Seed.prototype.toString = function () {
    return words.map(function (word) {
        return ("0000" + word.toString(16)).slice(-4);
    }).join('').toUpperCase();
};

Seed.prototype.nextSeed = function (n) {
    var seed = this.seed;
    n = n || 1;
    for (var frame = 0; frame < n; ++frame) {

        var a = [0x5D58, 0x8B65, 0x6C07, 0x8965];
        var c = [0, 0, 0x26, 0x9EC3];

        var nextSeed = [0, 0, 0, 0];
        var carry = 0;

        for (var cN = seed.length - 1; cN >= 0; --cN) {
            nextSeed[cN] = carry;
            carry = 0;

            var aN = seed.length - 1;
            var seedN = cN;
            for (; seedN < seed.length; --aN, ++seedN) {
                var nextWord = a[aN] * seed[seedN];
                carry += nextWord >>> 16;
                nextSeed[cN] += nextWord & 0xFFFF;
            }
            nextSeed[cN] += c[cN];
            carry += nextSeed[cN] >>> 16;
            nextSeed[cN] &= 0xFFFF;
        }

        seed = nextSeed;
    }
    return new Seed(seed);
}

Seed.prototype.advance = function (n) {
    var nextSeed = this.nextSeed(n);
    this.seed = nextSeed.seed;
    this.u32 = nextSeed.u32;
    this.l32 = nextSeed.l32;
}